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The Single UNIX &reg; Specification, Version 2<br>
Copyright &copy; 1997 The Open Group

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<h4><a name = "tag_000_005_572">&nbsp;</a>NAME</h4><blockquote>
getgroups - get supplementary group IDs
</blockquote><h4><a name = "tag_000_005_573">&nbsp;</a>SYNOPSIS</h4><blockquote>
<pre><code>

#include &lt;<a href="systypes.h.html">sys/types.h</a>&gt;
#include &lt;<a href="unistd.h.html">unistd.h</a>&gt;

int getgroups(int <i>gidsetsize</i>, gid_t <i>grouplist</i>[]);
</code>
</pre>
</blockquote><h4><a name = "tag_000_005_574">&nbsp;</a>DESCRIPTION</h4><blockquote>
The
<i>getgroups()</i>
function fills in the array
<i>grouplist</i>
with the current supplementary group IDs of the calling process.
<p>
The
<i>gidsetsize</i>
argument specifies the number of elements in the array
<i>grouplist</i>.
The actual number of supplementary group IDs stored in the
array is returned.
The values of array entries with indices greater than or equal to
the value returned are undefined.
<p>
If
<i>gidsetsize</i>
is 0,
<i>getgroups()</i>
returns the number of supplementary group IDs associated with the
calling process without modifying the array pointed to by
<i>grouplist</i>.
<p>
It is unspecified whether the effective group ID of the calling
process is included in, or omitted from, the returned list of
supplementary group IDs.
</blockquote><h4><a name = "tag_000_005_575">&nbsp;</a>RETURN VALUE</h4><blockquote>
Upon successful completion, the number of supplementary group IDs
is returned.
A return value of -1 indicates failure and
<i>errno</i>
is set to indicate the error.
</blockquote><h4><a name = "tag_000_005_576">&nbsp;</a>ERRORS</h4><blockquote>
The
<i>getgroups()</i>
function will fail if:
<dl compact>

<dt>[EINVAL]<dd>
The
<i>gidsetsize</i>
argument is non-zero and is less than the number of supplementary group IDs.

</dl>
</blockquote><h4><a name = "tag_000_005_577">&nbsp;</a>EXAMPLES</h4><blockquote>
None.
</blockquote><h4><a name = "tag_000_005_578">&nbsp;</a>APPLICATION USAGE</h4><blockquote>
None.
</blockquote><h4><a name = "tag_000_005_579">&nbsp;</a>FUTURE DIRECTIONS</h4><blockquote>
None.
</blockquote><h4><a name = "tag_000_005_580">&nbsp;</a>SEE ALSO</h4><blockquote>
<i><a href="getegid.html">getegid()</a></i>,
<i><a href="setgid.html">setgid()</a></i>,
<i><a href="systypes.h.html">&lt;sys/types.h&gt;</a></i>,
<i><a href="unistd.h.html">&lt;unistd.h&gt;</a></i>.
</blockquote><h4>DERIVATION</h4><blockquote>
Derived from the POSIX.1-1988 standard.
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UNIX &reg; is a registered Trademark of The Open Group.<br>
Copyright &copy; 1997 The Open Group
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